I don't know the Nikon close-up lenses, but I once tried a third-party closeup-lens on my 18-200 because I was not really satisfied with its macro capabilities. I gave the lens back a few days later, because the quality of the pics was miserable. It was not color aberations (that certainly a better closeup-lens can eliminate) but it was a visible lack of sharpness outside the center, even if stopped down to f11 or below.

I would certainly say, that the better approach would be to get as close as possible to the subject of your desire with the lens set to the longest focal length and apply a little magnification (2-3x) in SW afterwards. This yields a lower res pic (e.g. like from a 1-2.5 Mega pixel sensor) but is in my opinion better for the casual macro photo. Most SW should even apply some intelligent algorithm to make the pic look better than a 2.5MP original.

Today I'm the proud owner of the Nikko 105mm VR, which is the best solution to macro photography from Nikon.

And don't let third party lens manufacturers fool you with the macro capabilities of their zooms into believing, that their macro picture quality is good. It it almost impossible to get a decent 1:2 or below macro on any zoom lens. Then it is even better to buy a fixed length specialized macro from say sigma pref. the 105mm variety, because a good fixed length macro is much easier to construct. But you will certainly miss the image stab of the Nikkor 105mm VR. No third party manufacturer has a image stabilized macro (yet).

Hello Monelle, I've used extensively the 18-200 and it simply is not a good macro lens. If you're saving pennies, try the $90 18-55VR kit lens, and you'll be surprised with the results. Also check my topic "Inexpensive macro, autofocus extension tubes". Greetings from Brazil, Paulo.